FAULTY DEVICE

I bought a phone at PEP Cell in Berea Centre in Durban on 17 February 2022 and I went home with the device and charged overnight as per the manual. The next day when I was preparing to go to work I noticed that the battery had gone down from 100% to 80%. As I was about to leave my house, the battery was 75%. I took the phone to PEP in Musgrave Centre and they told me to leave the phone with them. Upon my return, they told me there was nothing wrong with the device and that the battery was being chowed by apps in the background. Thing is, I had not installed any apps and my mobile data was off the entire time. I told them I need to have the device exchanged and they told me I should go to PEP in Berea Centre where I bought the phone. I went to Berea Centre and requested for an exchanged, they refused and treated me really badly. They refuse to even refund me my money. I called the Customer Care Line and was told my details will be passed on to the Area Manager who would call me. I have waiting ever since with no one assisting me! This is 4th day of having a faulty phone that I don't want. I need help before the 7 day exchange policy lapse.